Development Of A New-style Ambulatory EEG Recorder

Ambulatory electroencephalography (AEEG) system is a portable micromachine and can record EEG data automatically. It deals with the recorded data through microcomputer's special analytical software, and can print the graph and the original report, in order to help the doctor to take conclusion. The AEEG monitoring has been proved that it can take good effects for clinical medicine. The machine has been used widely to diagnose encephalic disease.especially in epilepsy, cerebrovascular disease and paralytic disease. AEEG has more advantages than static EEG, because it can be used in the home setting and can record continuously 24 hours' or even up to 72 hours' EEG data, so increases the chance of recording an ictal event or interictal epileptiform discharges.Based on analyzing the character of EEG signal, we design the AEEG recorder with 18 channels. Some points are thinked over in the designing process and have been resolved at last, such as low power consumption,high anti-jamming ability,portable and so on. Its primary functions include EEG signal sampling,data filtering and storage, and wave displaying in real time. Primary parameter: Max noise input < 3uV, input impedance >100M Ω, CMRR >100dB.The hardware of the system involves EEG amplifier with 18 channels, the analog-digital converter, keyboard input module, wave displaying,storage of CF card and so on. This system uses the battery as supply power, and adopts instrumentation amplifier wtih high performance as preamplifier, so that we can improve the CMRR and input impedance, and decrease the line frequency noise effectively. All the component are selected by their character of SO footprint and low power consumption, so as to decrease the system power consumption and make it portable.The software of the system introduces the task queue, and this transact pattern improve the software modularization level and efficiency. The file...